Fruit Fly (Drosophila melanogaster)

Genetic variation at the Fruit Fly (Drosophila melanogaster) ADH (Alcohol dehydrogenase) locus

In Drosophila, the gene locus (Adh) for the enzyme alcohol dehydrogenase (ADH) has multiple alleles, two of which (Adh-f & Adh-s) produce two allozymes, one 'fast' (ADH-f) and the other 'slow' (ADH-s). Kreitman (1983) conducted a study to determine the genetic basis of the difference. In the data below, identify the DNA sequence difference between the two alleles (Adh-s & Adh-f ) responsible for the two allozymes, and identify the amino acid substitution responsible for the charge difference. Hint: the first two amino acids in the protein sequence are Lys - Leu.

   Adh-s      1 aaactggccc ccattaccgg cgtgacggct tacactgtga accccggcat cacccgcacc

  Adh-f      1 aaactggccc ccattaccgg cgtgacggct tacactgtga accccggcat cacccgcacc

  Adh-s     61 accctggtgc acaagttcaa ctcctggttg gatgttgagc ctcaggttgc tgagaagctc

  Adh-f     61 accctggtgc acacgttcaa ctcctggttg gatgttgagc ctcaggttgc tgagaagctc

  Adh-s    121 ctggctcatc ccacccagcc ctcgttggcc tgcgccgaga acttcgtcaa ggctatcgaa

  Adh-f    121 ctggctcatc ccacccagcc ctcgttggcc tgcgccgaga acttcgtcaa ggctatcgaa

  Adh-s    181 ctgaaccaga acggagccat ctggaaactg gacttgggca ccctggaggc catccagtgg

  Adh-f    181 ctgaaccaga acggagccat ctggaaactg gacttgggca ccctggaggc catccagtgg

  Adh-s    241 accaagcact gggactccgg catctaa

  Adh-f    241 accaagcact gggactccgg catctaa